What do posters do?
Posters are more than just pieces of paper. A good poster effectively conveys its message, whether the message is urging the beholder to purchase the latest cool piece of technology or informing the beholder about the importance of brushing your teeth. No matter what the purpose is, posters intend to manipulate our actions. Posters range from economic purposes to cultural ones, as well as political and social purposes; they enlighten and give us information, publicize/ advertise a product, and entertain us. Posters are meant to inform, stimulate, activate, mobilize, provoke, convince, and motivate.Poster Design
Posters communicate their message through picture and text, which in some cases is more effective, and in others, not so much. A poster is meant to be eye-catching and so incredible that it is impossibly avoidably. Different posters intend to draw different people in depending on their age, character, level of education, and mood. However, some poster designs are so irresistible to everyone which makes us ask: why? There is no answer to this, for it is impossible to explain design and its effect. However, color, composition, contrast, proportion, quantity, rhythm, dynamics, extension, etc... all contribute to how impactful a poster is.
General Demands
Posters should not be confusing. They need to be easily understood, with the message easily conveyed, and they need to be legible. Posters must be interesting and provoke the person who sees them. Because that's what posters' purpose is: to inspire someone to do something or learn more. A poster designer must keep in mind that a poster needs to be legible from a distance; this means that large shapes should be incorporated. Up close the poster should have detailing that does not take away or confuse from the main idea. In addition, posters should be memorable to the viewer. 
Lettering
Lettering combined with picture has a strong effect. Lettering that is inside a picture implies that it is a part of the whole composition. As well as if it is similar in spacing, color, and size. Lettering should be concise and simple to quickly get across information.
Shapes
The purpose of a poster should be clearly executed by shapes. Shapes should produce a well composed surface that is very interesting and easily and quickly readable. Different shapes produce different effects: The diagonal shape and the rythmitzed form produces a dynamic effect, the correct trimming supports the effect, a lapidary shape of the picture can release a strong effect, horizontal and vertical shapes produce a static form, etc... Overlapping wording and pictures creates unity, increases dynamic and rhythmic effects, as well as the impression of depth and elegance of the poster. To emphasize the main point of a poster, it is important to place the main optic point in the center. The purpose of a poster should be erased of any irrelevant or superfluous details because these things derail from the significance of a poster.
Color
Color is an important element off an effect poster. Color expresses emotion. It is innovative, strong, fascinating, and expressive. Color, through its psychology, can clarify situations and evoke different emotions.My Thoughts
There is more to posters than what meets the eye. It is amazing to see all of the key elements that make an effective poster. It is fascinating how color, shape, and text, three simple things, can be executed in such different ways to communicate a different message and stimulate people to do and think certain things. I will keep in mind that such simple aspects make a huge difference in the overall appearance of a project, whether it's a poster or any other kind of art.
